I. Technical Field
This disclosure relates generally to apparatus and methods for position estimation of a mobile terminal, and more particularly to estimation of positions where satellite positioning systems may be inadequate, such as for indoor positioning.
II. Background
Positioning estimation (PE) engines are currently used to determine a position of a mobile terminal using GPS navigation, dead reckoning, signal measurements or a combination of any two or the three. For indoor navigation over a long term, a PE engine may be forced to rely solely on various signal measures, such as signal strength (e.g., RSSI or received signal strength indication values) and/or signal transmission time (e.g., RTT or round trip time values).